Abstract
A new type of lube oil cleaning system was successfully developed for semi-permanent use of oil by always keeping oil clean with no oil change and no waste oil. This system has been put into practical use in many marine diesel engines and in some other fields. Also, the possibility of semi-permanent use of engines themselves was expected based on the field data. A ship test for 7 years has verified the expected semi-permanent use of engines with almost no wear and constant thermal efficiency during the test. In this paper, the characteristics of the oil cleaning system and the results of the test are presented.
